<template>

  <div class="app-container">
     
    <h2 style="text-align: center;">发布新课程</h2>
    <!-- 课程发布步骤跳转 -->
    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">

        <!-- 课程标题 -->
        <el-form-item label="课程标题">
            <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>

        <!-- 课程分类 -->
        <el-form-item label="课程分类">
            <el-select v-model="courseInfo.subjectParentId" 
                placeholder="一级分类" @change="subjectLevelOneChanged">
                <el-option v-for="subject in subjectOneList" :key="subject.id"
                    :label="subject.title" :value="subject.id"/>
            </el-select>   

            <!-- 二级分类 -->
            <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
                <el-option v-for="subject in subjectTwoList" :key="subject.id"
                    :label="subject.title" :value="subject.id"/>
            </el-select>
        </el-form-item> 

        <!-- 课程讲师 -->
        <el-form-item label="课程讲师">
            <el-select v-model="courseInfo.teacherId" placeholder="请选择">
                <el-option v-for="teacher in teacherList" :key="teacher.id"
                    :label="teacher.name" :value="teacher.id"/>
            </el-select>
        </el-form-item>

        <!-- 总课时 -->
        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>

        <!-- 课程简介 -->
        <el-form-item label="课程简介">
            <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>

        <!-- 课程封面-->
        <el-form-item label="课程封面">
            <el-upload :show-file-list="false" 
                :on-success="handleAvatarSuccess" :before-upload="beforeAvatarUpload" 
                :action="BASE_API+'/eduoss/fileoss/upload'"  class="avatar-uploader"  >
                <div width="100px" height="100px" border-radius="45px" background-color="red">
                    <img :src="courseInfo.cover" width="100px" height="100px" >
                </div>
               
            </el-upload>
        </el-form-item>

        <!-- 课程价格 -->
        <el-form-item label="课程价格">
            <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>

        <!-- 下一步按钮 -->
        <div>
            <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
        </div>
    </el-form>
  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject' 
import Tinymce from '@/components/Tinymce' //引入组件
export default {
    components:{
        Tinymce
    },
    data() {
        return {
            saveBtnDisabled:false,
            courseInfo:{
                title: '',
                subjectId: '',//二级分类id
                subjectParentId:'',//一级分类id
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: '/static/02.jpg',
                price: 0
            },
            courseId:"",
            BASE_API: process.env.BASE_API, // 接口API地址
            teacherList:[],//封装所有的讲师
            subjectOneList:[],//一级分类
            subjectTwoList:[]//二级分类
        }   
    },
    created() {
        this.init()
    },
     watch:{  //监听
        $route(to,from){ //路由变化方式，路由发生变化，方法就会执行
            this.init()
        }
    },
    methods:{
        //页面渲染前调用
        init(){
            //获取路由id值
            if(this.$route.params && this.$route.params.id){
                this.courseId = this.$route.params.id
                //根据id查询课程基本信息
                this.getCourseInfoId()
            }else{
                this.courseInfo = {
                    title: '',
                    subjectId: '',//二级分类id
                    subjectParentId:'',//一级分类id
                    teacherId: '',
                    lessonNum: 0,
                    description: '',
                    cover: '/static/02.jpg',
                    price: 0
                }
            }
            this.getListTeacher()
            this.getOneSubject()
        },
        //根据课程id查询章节和小节
        getCourseInfoId(){
          course.getCourseInfoId(this.courseId)
            .then(response=>{
                //在courseInfo课程基本信息中，包含一次分类id和二级分类id
              this.courseInfo = response.data.courseInfoVo
              //1 查询所有的分类，包含一级和二级
              subject.getSubjectList()
                .then(response=>{
                    //2 获取所有一次分类
                    this.subjectOneList = response.data.list
                    //3 把所有的一级分类数组进行遍历
                    for(let i=0;i<this.subjectOneList.length;i++){
                        //获取每个一次分类
                        let oneSubject = this.subjectOneList[i]
                        //比较当前courseInfo里面一级分类id和所有的一级分类id
                        if(this.courseInfo.subjectParentId == oneSubject.id){
                            //获取一次分类所有的二级分类
                            this.subjectTwoList = oneSubject.twoSubjects

                        }
                    }
                })
              //初始化所有讲师
              this.getListTeacher()
            })
        },
        //上传封面成功调用的方法
        handleAvatarSuccess(res, file) {
            this.courseInfo.cover = res.data.url
        },
        //上传之前调用的方法
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2
            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }

            return isJPG && isLt2M
        },
        //点击某个一级分类，触发change，显示对应二级分类
        subjectLevelOneChanged(value) {
            //value就是一级分类id值
            //遍历所有的分类，包含一级和二级
           
            for(var i=0;i<this.subjectOneList.length;i++) {
                //每个一级分类
                var oneSubject = this.subjectOneList[i]
                //判断：所有一级分类id 和 点击一级分类id是否一样
                if(value === oneSubject.id) {
                    //从一级分类获取里面所有的二级分类
                    this.subjectTwoList = oneSubject.twoSubjects
                    //把二级分类id值清空
                    this.courseInfo.subjectId = ''
                }
            }
        },
        //查询所有的一级分类
        getOneSubject() {
            subject.getSubjectList()
                .then(response => {
                    this.subjectOneList = response.data.list
                })
        },
        //查询所有的讲师
        getListTeacher() {
            course.getListTeacher()
                .then(response => {
                    this.teacherList = response.data.items
                })
        },
        //保存课程信息
        addCourse(){
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '添加课程信息成功!'
                    });
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/'+response.data.courseId})
                })
        },
        //修改课程信息
        updateCourse(){
            course.updateCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '修改课程信息成功!'
                    });
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/'+this.courseId})
                })      
        },
        //保存并跳转到下一步
        saveOrUpdate() {
            //判断添加还是修改
            if(!this.courseInfo.id){
                //添加
                this.addCourse()
            }else{
                //修改
                this.updateCourse()
            }
            
        }
    }
}
</script>
<style scoped>
    .tinymce-container{
        line-height: 29px;
    }
</style>
